Host material, organic electroluminescent material containing double hosts and application

Abstract

The invention belongs to the field of organic electroluminescent materials, and discloses a host material, an organic electroluminescent material containing double hosts and application. The double-host-containing organic electroluminescent material comprises a first host material and a second host material, the first host material is a compound having structures represented by general formulas 1-1 and 1-2, and the second host material is a compound having a structure represented by a general formula 2. The organic electroluminescent material containing the double hosts is applied to a specific luminescent device, and has the advantages of low driving voltage, high luminous efficiency and long service life.

Description

Technical Field

[0001] The present invention belongs to the field of organic electroluminescent materials, and particularly relates to a host material, an organic electroluminescent material containing a double host, and an application thereof. Background Art

[0002] An Organic Light Emission Device (OLED) can be used to manufacture new display products and new lighting products, and is gradually replacing existing liquid crystal displays and fluorescent lamp lighting, with a very broad market application prospect. The structure of an OLED is like a sandwich, including electrode material layers and organic functional materials sandwiched between different electrode material layers. These functional materials are stacked together according to different uses to jointly form an OLED. As a current device, when a voltage is applied to the two electrodes of the OLED, and positive and negative charges in the organic layer functional material layer are further recombined in the light-emitting layer through the action of an electric field, OLED electroluminescence is generated.

[0003] Currently, OLED display technology has been applied in fields such as smartphones and tablets, and the next goal is to continue to expand into large-size application fields such as televisions. However, compared with the actual product application requirements, the performance of OLEDs such as luminous efficiency and service life still needs to be further improved.

[0004] The efficiency of OLEDs is improved through host-guest doping in the light-emitting layer. Since the radiative transition of triplet excitons of most organic molecules is forbidden and contributes little to electroluminescence, doping with organometallic complexes such as platinum, iridium, and osmium can transfer the triplet excitons of organic molecules to the triplet state of the metal complex, thereby greatly improving the efficiency of organic light-emitting devices. However, triplet-triplet annihilation (TTA) occurs during the transfer process of triplet excitons, resulting in energy loss and causing efficiency roll-off of organic light-emitting devices.

[0005] Currently, the poor performance of organic electroluminescent devices is still a technical problem that needs to be urgently solved during their use. For example, there are problems such as too high driving voltage, too low luminous efficiency, or short lifespan, which all affect the application fields of organic electroluminescent devices.

[0006] Therefore, how to develop an organic electroluminescent material containing a double host with a long lifespan and a low driving voltage, its preparation method, and an organic electroluminescent device are technical problems that need to be urgently solved by those skilled in the art. Summary of the Invention

[0007] In view of this, aiming at the deficiencies of the prior art, the present invention discloses and provides a host material, an organic electroluminescent material containing a dual host, and applications thereof. Applying the organic electroluminescent material containing a dual host of the present invention to a specific light-emitting device has low driving voltage, high luminous efficiency, and long service life.

[0008] It should be noted that the present invention provides an organic electroluminescent device with a dual host structure. By using this dual host material, triplet excitons can be dispersed on two hosts. Because the triarylamine structure has a relatively high HOMO energy level, it is beneficial to the injection and transport of holes. At the same time, the rigid structure of triarylamine helps to improve the thermal stability of the material. Materials containing triarylamine usually have a relatively high glass transition temperature and are suitable for high-temperature processing. The triarylamine structure can improve the fluorescence quantum yield of the material through molecular design. By modifying the triarylamine structure, the emission wavelength of the material can be adjusted to achieve luminescence of different colors; and the triarylamine structure is easy to be chemically modified, facilitating the regulation of the optoelectronic properties of the material. The triarylamine structure can be combined with other conjugated systems to expand the conjugated length of the material and improve the optoelectronic properties. Through molecular design, the triarylamine structure helps to achieve bipolar transport of electrons and holes, improving the device efficiency.

[0009] The high electron affinity of the triazine ring helps to improve the electron transport ability of the material. The triazine structure usually has a relatively low LUMO energy level, which is beneficial to electron injection and transport. The rigidity of the triazine ring enhances the thermal stability of the material and is suitable for high-temperature environments. Materials containing triazine usually have a relatively high decomposition temperature and are suitable for high-temperature processing. The triazine structure can improve the fluorescence quantum yield of the material and enhance the luminous efficiency. The triazine structure can be combined with other conjugated systems to expand the conjugated length of the material and improve the optoelectronic properties. The triazine structure helps to achieve bipolar transport of electrons and holes, improving the device efficiency. Through its electron affinity, thermal stability, and luminescence properties, the triazine structure can improve the performance of organic light-emitting materials. Therefore, the dual host can reduce triplet-triplet annihilation (TTA), while reducing the driving voltage of the organic electroluminescent device, and improving the luminous efficiency and lifespan of the device.

[0010] To achieve the above object, the following technical solutions are adopted:

[0011] The first technical object of the present invention is to provide a host material, and the structure of the host material is shown in General Formula 1-1 and General Formula 1-2:

[0012]

[0013] Wherein,

[0014] Ring A is selected from substituted or unsubstituted (C6-C18) aryl; Ring B is selected from substituted or unsubstituted (C6-C18) aryl, substituted or unsubstituted (C6-C18) heteroaryl; Ring C is selected from hydrogen, substituted or unsubstituted (C6-C18) aryl, substituted or unsubstituted (C6-C18) heteroaryl;

[0015] X is independently selected from N, O, S;

[0016] L is selected from a linking bond, substituted or unsubstituted (C6-C30) aryl.

[0017] Furthermore, Ring A and Ring B are each independently selected from substituted or unsubstituted phenyl; X is independently selected from O.

[0018] In the above technical solution,

[0019] The "substituted or unsubstituted" means that the group may be unsubstituted or substituted by one or more substituents. The "substitution" means that a hydrogen atom bonded to a carbon atom of the compound becomes another substituent, and there is no limitation on the substitution position as long as it is the position where the hydrogen atom is substituted, that is, the position where the substituent can be substituted. When two or more substituents are substituted, the two or more substituents may be the same or different from each other.

[0020] Heteroaryl includes monocyclic aromatic groups and polycyclic aromatic ring systems containing at least one heteroatom, and the heteroatoms include but are not limited to O, S, N.

[0021] The substituents in the "substituted or unsubstituted" are selected from deuterium, fluorine, C1-C10 alkyl, deuterium-substituted C1-C10 alkyl, C3-C10 cycloalkyl, C3-C10 heterocycloalkyl, and the heteroatoms thereof are selected from O, S, N; and the substituents in the "substituted or unsubstituted" may also be selected from the following structures:

[0022]

[0023] The general formulas 1-1 and 1-2 specifically have the following structures, but are not limited thereto:

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044] The second technical object of the present invention is to provide an organic electroluminescent material containing a double host. The organic electroluminescent material containing a double host includes a first host material and a second host material. The first host material is the above-mentioned host material, and the second host material has a structure shown in General Formula 2:

[0045]

[0046] Wherein,

[0047] D1, D2, and D3 are each independently selected from a substituted or unsubstituted (C6-C42) aryl group or a substituted or unsubstituted (C3-C30) heteroaryl group;

[0048] L1 and L2 are selected from a linking bond, a substituted or unsubstituted (C6-C30) aryl group.

[0049] Further, D1 and D2 are selected from a (C6-C18) substituted or unsubstituted aryl group;

[0050] D3 is selected from a substituted or unsubstituted (C6-C36) aryl group or a substituted or unsubstituted (C3-C30) heteroaryl group;

[0051] L1 and L2 are selected from linking groups, (C6-C18) substituted or unsubstituted aryl groups.

[0052] Furthermore, D1 is selected from substituted or unsubstituted phenyl, biphenyl, terphenyl; D2 is selected from substituted or unsubstituted phenyl, naphthyl, biphenyl, terphenyl, benzo[ghi]perylenyl; D3 is selected from substituted or unsubstituted (C6-C30) aryl groups, substituted or unsubstituted (C3-C30) heteroaryl groups; L1 is a linking group, and L2 is a linking group or phenyl, naphthyl.

[0053] In the above technical solution,

[0054] The term "substituted or unsubstituted" means that the group may be unsubstituted or substituted by one or more substituents. The term "substituted" means that a hydrogen atom bonded to a carbon atom of the compound is replaced by another substituent, and there is no restriction on the substitution position as long as the position is where the hydrogen atom is substituted, that is, the position where the substituent can be substituted. When two or more substituents are substituted, the two or more substituents may be the same or different from each other.

[0055] Heteroaryl groups include monocyclic aromatic groups and polycyclic aromatic ring systems containing at least one heteroatom. The heteroatoms include, but are not limited to, O, S, and N.

[0056] The substituents in the "substituted or unsubstituted" are selected from deuterium, fluorine, C1-C10 alkyl groups, deuterium-substituted C1-C10 alkyl groups, C3-C10 cycloalkyl groups, C3-C10 heterocycloalkyl groups, and the heteroatoms thereof are selected from O, S, N; and the substituents in the "substituted or unsubstituted" may also be selected from the following structures:

[0057]

[0058] In the technical solution of the present invention, General Formula 2 is selected from any one of the following compounds, but is not limited to the following structures:.

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071] The present invention also provides a preparation method of the above-mentioned organic electroluminescent material containing a dual host, and its synthetic route and preparation steps are as follows:

[0072] (1) Preparation of intermediates RA and RB:

[0073]

[0074] Under a nitrogen atmosphere, 6-bromo-2-phenylbenzoxazole (CAS: 537025-33-5) (1 eq), 5-bromo-2-phenyl-1,3-benzoxazole (CAS: 69918-19-0) (1 eq), a chlorine-containing 2-aldehyde phenylboronic acid compound (1 - 1.2 eq), potassium carbonate (2.5 - 3 eq), toluene (100 - 110 mL), ethanol (50 - 55 mL), and water (50 - 55 mL) are successively added to a round-bottom flask. After stirring for 10 min, tetrakis(triphenylphosphine)palladium Pd(pph3)4 (0.02 - 0.03 eq) is added, and the temperature is raised to 80 °C and stirred for 10 hours. After the temperature of the reaction system drops to room temperature, a solid precipitates. The reaction solution is filtered to obtain a crude product. After the crude product is rinsed with water, it is continuously rinsed with ethanol, and finally rinsed with n-heptane and then dried to obtain the RA-a series (RB-a series);

[0075]

[0076] Under a nitrogen atmosphere, chloromethyl ether triphenylphosphine (0.7 - 0.85 eq) and tetrahydrofuran are successively added to a round-bottom flask. The temperature of the system is lowered to -10 °C to 15 °C using liquid nitrogen, and potassium tert-butoxide is added to the system while controlling the temperature of the system at -10 °C to 15 °C. After maintaining the temperature for 2 hours, the RA-a series (RB-a series) (1 eq) is weighed and dissolved in 10 times of tetrahydrofuran. Then, it is separately dropped into the system using a constant-pressure burette and added dropwise within 1 hour, while controlling the temperature of the system at -5 °C. After adding the drops, the temperature is maintained for 2 hours. After the temperature of the reaction solution rises to room temperature, the organic phase is separated by washing with water and extraction, and the organic phase is dried using anhydrous magnesium sulfate, and the solvent in the organic phase is removed under reduced pressure to obtain a crude product. Using dichloromethane / n-heptane as an eluent, the crude product is purified by silica gel column chromatography to obtain the RA-b series (RB-b series).

[0077]

[0078] Under nitrogen atmosphere, RA-b series (RB-b series) (1 eq), Eaton's reagent (0.2-0.3 eq), and chlorobenzene were added to a three-necked flask in sequence, and stirring and heating were started. The temperature was raised (135-140° C.) to reflux and the reaction was carried out for 1 hour. After the reaction was stopped, the system temperature was lowered to room temperature, and the reaction solution was extracted with water to separate the organic phase. The organic phase was dried over anhydrous magnesium sulfate, and the solvent in the organic phase was removed under reduced pressure to obtain a crude product. The crude product was purified by silica gel column chromatography using toluene / n-heptane as an eluent to obtain RA series (RB series).

[0079] (2) Synthesis of General Formula 1-1 and 1-2

[0080]

[0081] Under nitrogen protection, weigh RA (RB) series (1 eq), reactant 1 (2) (1-1.1 eq), sodium tert-butoxide (2-3 eq) and put them into the reaction system, add toluene, catalyst tris (dibenzylideneacetone) palladium (0.02-0.04 eq) and tri-tert-butylphosphine (0.04-0.06 eq), reflux at 100-120 ° C for 24 h under nitrogen protection, then cool to 25 ° C, add purified water, stir for 30 min, stand for stratification, separate the liquids, and perform column chromatography to obtain the compounds of the general formula 1-1 and the general formula 1-2 shown;

[0082] (3) Synthesis route of general formula 2

[0083]

[0084] Under nitrogen protection, reactant 1 (1 eq), reactant 2 (1-1.2 eq), and potassium carbonate (3-4 eq) were weighed and put into the reaction system, and toluene, ethanol, water, and catalyst tetrakis(triphenylphosphine)palladium (0.05-0.08 eq) were added. The mixture was refluxed at 90-100° C. for 24 h under nitrogen protection, and then cooled to 25° C., filtered, and solid column chromatography was performed to obtain the compound H-1 shown;

[0085] Under nitrogen protection, weigh H-1 (1 eq), reactant 2-1 (1-1.2 eq), potassium carbonate (3-4 eq) and put them into the reaction system, add toluene, ethanol, water and catalyst tetrakis(triphenylphosphine)palladium (0.05-0.08 eq), reflux at 90-100°C for 24 h under nitrogen protection, then cool to 25°C, filter, and perform solid column chromatography to obtain the compound H-2 shown;

[0086] Under a nitrogen protection system, weigh H-2 (1 eq), reactant 2-2 (1-1.2 eq), and potassium carbonate (3-4 eq) and put them into the reaction system. Add toluene, ethanol, water, and the catalyst tetrakis(triphenylphosphine)palladium (0.05-0.08 eq). Reflux at 90-100 °C for 24 h under nitrogen protection, then cool to 25 °C, filter by suction, and perform solid column chromatography to obtain the shown compound H (general formula 2).

[0087] The third technical object of the present invention is to provide an application of an organic electroluminescent material containing a double host in the preparation of an organic electroluminescent device.

[0088] Specifically, the organic electroluminescent device includes a first electrode, a second electrode, and an organic electroluminescent material layer disposed between the first electrode and the second electrode; and, the organic electroluminescent material layer includes a light-emitting layer; the light-emitting layer includes a doping material and the double-host organic electroluminescent material as described above;

[0089] Among them, the mass ratio of the double-host organic electroluminescent material to the doping material is (1-99):(99-1).

[0090] More specifically, the organic electroluminescent device includes an anode, a hole transport region, a light-emitting layer, an electron transport region, and a cathode. The light-emitting layer includes a first host material represented by general formula 1-1 and general formula 1-2, and a second host material represented by general formula 2.

[0091] As the anode material, materials with a large work function are usually preferably used to enable smooth hole injection into the organic material layer. The anode materials that can be used for the first electrode of the organic electroluminescent device of the present invention include: metals, such as vanadium, chromium, copper, zinc, and gold, or their alloys; metal oxides, such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); combinations of metals and oxides, such as ZnO:Al or SnO2:Sb; conductive polymers, such as poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDOT), polypyrrole, and polyaniline, but not limited thereto.

[0092] As the cathode material, materials with a small work function are usually preferably used to enable smooth electron injection into the organic material layer. The cathode materials that can be used for the second electrode of the organic electroluminescent device of the present invention include: metals, such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, or their alloys; multi-layer structure materials, such as LiF / Al or LiO2 / Al; and so on, but not limited thereto.

[0093] The hole injection layer material is a material that receives holes from the anode at a low voltage, and the highest occupied molecular orbital (HOMO) of the hole injection material is preferably between the work function of the anode material and the HOMO of the surrounding organic material layer. The hole injection materials include metal porphyrins, oligothiophenes, arylamine-based organic materials, hexanitrile hexaazatriphenylene-based organic materials, quinacridone-based organic materials, perylene-based organic materials, anthraquinone, and conductive polymers based on polyaniline and polythiophene, etc.

[0094] The hole transport layer material is a material that can receive holes from the anode or the hole injection layer and transport the holes to the light-emitting layer, and has a high hole mobility; and the hole transport layer materials include arylamine-based organic materials, conductive polymers, block copolymers having both a conjugated part and a non-conjugated part, etc., but are not limited thereto.

[0095] An electron blocking layer can be provided between the hole transport layer and the light-emitting layer. As the electron blocking layer, materials known in the art can be used, such as arylamine-based organic materials.

[0096] The host material of the light-emitting layer is selected from the structure of the present invention.

[0097] A hole blocking layer can be provided between the electron transport layer and the light-emitting layer, and materials known in the art can be used, such as triazine-based compounds.

[0098] The electron transport layer can play a role in promoting electron transport. The electron transport material is advantageously a material that receives electrons from the cathode and transports the electrons to the light-emitting layer and has a high electron mobility. It includes: Al complexes of 8-hydroxyquinoline; complexes containing Alq3; organic radical compounds; hydroxyflavone-metal complexes, etc., but are not limited thereto. The thickness of the electron transport layer can be 1 nm to 50 nm. The electron transport layer with a thickness of 1 nm or more has the advantage of preventing the degradation of electron transport characteristics, and the thickness of 50 nm or less has the advantage of preventing the increase in driving voltage caused by the too thick electron transport layer.

[0099] The electron injection layer can play a role in promoting electron injection, and the electron injection material preferably has the ability to transport electrons, has an injection electron effect from the cathode, has an excellent electron injection effect on the light-emitting layer or the light-emitting material, prevents the excitons generated in the light-emitting layer from migrating to the hole injection layer, and in addition, has an excellent thin film forming ability. Specific examples thereof include fluorenone, anthraquinone dimethane, biphenylquinone, thiopyran dioxide, oxazole, dioxazole, triazole, imidazole, perylene tetracarboxylic acid, fluoreneylidene methane, anthrone, etc. and their derivatives, metal complexes, nitrogen-containing five-membered ring derivatives, etc., but are not limited thereto.

[0100] Depending on the materials used, the above-mentioned organic electroluminescent device can be a top-emission type, a bottom-emission type, or a double-sided emission type.

[0101] In addition, the organic electroluminescent device described in the present invention can be used in organic solar cells, electronic papers, organic photoreceptors, or organic thin-film transistors.

[0102] From the above technical solutions, it can be seen that compared with the prior art, the present invention has the following beneficial effects:

[0103] The organic electroluminescent material provided by the present invention is a double-host organic compound. Based on the advantages of strong electron transport performance, high thermal stability, high glass transition temperature, hole injection and transport, and high hole mobility of triarylamine and triazine itself, the modified triarylamine and triazine are used as the double-host structure and different combinations are carried out to achieve bipolar transport of electrons and holes. After being used in an organic electroluminescent device, it can reduce triplet-triplet annihilation (TTA), greatly improve the device performance, and while reducing the driving voltage of the organic electroluminescent device, it can also improve the efficiency and lifespan of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0104] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0105] Figure 1 1H NMR spectrum of compound R011. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0106] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention and the relevant drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0107] The present invention specifically discloses a host material and a preparation method of an organic electroluminescent material containing a double host.

[0108] It should be noted that the values given in the following embodiments are as accurate as possible. However, those skilled in the art understand that due to inevitable measurement errors and experimental operation problems, each number should be understood as an approximate number rather than an absolutely accurate value.

[0109] Refer to the following common general knowledge:

[0110] "Transition Metal Organometallic Chemistry" (Original Sixth Edition), Robert H. Crabtree, Publisher: East China University of Science and Technology Press, Publication Date: 2017-09-00, ISBN: 978-7-5628-5111-0, Page 388.

[0111] "Experimental Course of Organic Chemistry and Optoelectronic Materials", Chen Runfeng, Publisher: Southeast University Press, Publication Date: 2019-11-00, ISBN: 9787564184230, Page 174.

[0112] Example 1: Preparation of Intermediates RA and RB

[0113]

[0114] Under a nitrogen atmosphere, 6-bromo-2-phenylbenzoxazole (CAS: 537025-33-5) (36.48 mmol), 2-chloro-6-formylphenylboronic acid (CAS: 2572469-70-4) (36.48 mmol), potassium carbonate (109.44 mmol), toluene (110 mL), ethanol (55 mL), and water (55 mL) were successively added to a round-bottom flask. After stirring for 10 min, tetrakis(triphenylphosphine)palladium Pd(pph3)4 (1.09 mmol) was added, and the temperature was raised to 80 °C and stirred for 10 hours. After the temperature of the reaction system dropped to room temperature, a solid precipitated. The reaction solution was filtered to obtain the crude product. After washing the crude product with water, it was further washed with ethanol and finally with n-heptane, and then dried to obtain RA-1a (8.8 g, yield 72.3%).

[0115]

[0116] Under a nitrogen atmosphere, chloromethyl ether triphenylphosphine (20.37 mmol) and tetrahydrofuran (80 mL) were successively added to a round-bottom flask. The temperature of the system was lowered to -10 °C to 15 °C using liquid nitrogen, and potassium tert-butoxide (31.16 mmol) was added to the system while controlling the temperature of the system at -10 °C to 15 °C. After maintaining the temperature for 2 hours, RA-1a (23.97 mmol) was weighed and dissolved in 10 times the amount of tetrahydrofuran, and then dropped into the system using a constant-pressure burette over 1 hour while controlling the temperature of the system at -5 °C. After dropping, the temperature was maintained for 2 hours. After the temperature of the reaction solution rose to room temperature, the organic phase was separated by washing with water and extraction, and the organic phase was dried with anhydrous magnesium sulfate, and the solvent in the organic phase was removed under reduced pressure to obtain the crude product. The crude product was purified by silica gel column chromatography using dichloromethane / n-heptane as the eluent to obtain RA-1b (4.91 g, yield 56.6%).

[0117]

[0118] Under a nitrogen atmosphere, RA-1b (13.54 mmol), Eaton's reagent (4.06 mmol), and chlorobenzene (49 mL) were added to a three-necked flask in sequence, and the mixture was stirred and heated to 140°C until reflux, and the reaction was carried out for 1 hour. After the reaction was stopped, the system temperature dropped to room temperature, and the reaction solution was extracted with water to separate the organic phase. The organic phase was dried over anhydrous magnesium sulfate, and the solvent in the organic phase was removed under reduced pressure to obtain a crude product. The crude product was purified by silica gel column chromatography using toluene / n-heptane as an eluent to obtain RA-1 (2.68 g, yield 60.1%).

[0119] The synthesis methods of the remaining RA-2, RA-3, RA-4, RB-1, RB-2, RB-3, and RB-4 are the same as those of RA-1.

[0120]

[0121] Example 2: Preparation of Compound R011

[0122]

[0123] Under nitrogen protection, RA-3 (30 mmol), reactant 1 (CAS: 21585819-05-8) (30 mmol), sodium tert-butoxide (60 mol) were weighed and put into the reaction system, and 120 ml of toluene, catalyst tri(dibenzylideneacetone) palladium (0.6 mmol) and tri-tert-butylphosphine (1.2 mmol) were added. The mixture was refluxed at 120 ° C for 24 h under nitrogen protection, and then cooled to 25 ° C, 120 mL of purified water was added, and the mixture was stirred for 30 min, then allowed to stand for stratification, separated, and subjected to column chromatography to obtain the compound R011 shown (test value: 704.41; 15.38 g, yield 72%).

[0124] Its PLC purity is greater than 99%.

[0125] Example 3: Preparation of Compound H001

[0126]

[0127] Under a nitrogen protection system, weigh reactant 1 (CAS: 108-77-0) (271.14 mmol), reactant 2 (CAS: 98-80-6) (813.43 mmol), and potassium carbonate (813.43 mol) and place them into the reaction system. Add 500 ml of toluene, 250 ml of ethanol, 250 ml of water, and the catalyst tetrakis(triphenylphosphine)palladium (13.56 mmol). Reflux at 90 °C for 24 h under nitrogen protection, then cool to 25 °C, filter by suction, and perform solid column chromatography to obtain the shown compound H001 (test value: 309.37; 83.9 g, yield 62.2%).

[0128] Its HPLC purity is greater than 99%.

[0129] Device Example 1: Preparation of an organic light-emitting device

[0130] ITO anode: The ITO (indium tin oxide) glass substrate with a coating thickness of is washed twice in distilled water, ultrasonically washed for 30 min, then repeatedly washed twice with distilled water and ultrasonically washed for 10 min. After the washing is completed, it is ultrasonically washed with methanol, acetone, and isopropyl alcohol in sequence (each washing for 5 min), dried, and then transferred to a plasma cleaner for washing for 5 min to obtain the ITO anode.

[0131] HIL (hole injection layer): In an evaporation coater, vacuum evaporate 4,4',4”-tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA) on the ITO anode to form a hole injection layer.

[0132] HTL (hole transport layer): Vacuum evaporate NPB (i.e., N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine) on the hole injection layer to form a hole transport layer.

[0133] Light-emitting layer: The light-emitting layer includes a first host material, a second host material, and a guest dopant. After forming the hole injection layer and the hole transport layer, form the light-emitting layer on the HTL: Introduce the first host compound organic light-emitting device and the second host compound organic light-emitting device as hosts into two small chambers of a vacuum vapor deposition device respectively, and introduce the compound Z1 as a dopant into another small chamber. Evaporate the two host materials at a rate of 1:1, and simultaneously evaporate the dopant material at different rates for deposition with a doping amount of 3 wt% based on the total amount of the host and the dopant to form a light-emitting layer with a thickness of 40 nm on the second hole transport layer.

[0134] HBL (Hole Blocking Layer): Vacuum deposit bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-olato)aluminum (BAlq) on the light-emitting layer to form a hole blocking layer.

[0135] ETL (Electron Transport Layer): Vacuum deposit tris(8-hydroxyquinoline) aluminum (Alq3) on the hole blocking layer to form an electron transport layer.

[0136] EIL (Electron Injection Layer): Vacuum deposit LiF2 on the electron transport layer to form an electron injection layer.

[0137] Cathode: Deposit Al on the electron injection layer to form a cathode, and thus an organic electroluminescent device can be obtained.

[0138] Referring to the preparation method of the organic electroluminescent device provided in Device Example 1, another 34 organic electroluminescent compounds were respectively selected to replace the first host compound organic electroluminescent device and the second host compound organic electroluminescent device for the evaporation of the host material, and the organic electroluminescent devices of the corresponding compounds were prepared.

[0139] Red light doping material (Z1)

[0140]

[0141] Device Examples 2 - 17, Comparative Examples 1 - 7 and Parallel Examples 1 - 6

[0142] The device manufacturing processes of Device Examples 2 - 17, Comparative Examples 1 - 7 and Parallel Examples 1 - 6 are exactly the same, and the same substrate material and electrode material are used, and the film thickness of the electrode material is also kept consistent. The difference lies in that: the two host materials are different, and the corresponding first host compound and second host compound in Table 1 are respectively selected, and the specific parameters are shown in Table 1.

[0143] Table 1 shows the parameters used in Device Examples 1 - 17, Comparative Examples 1 - 7 and Parallel Examples 1 - 6

[0144] Table 1

[0145]

[0146]

[0147] The structure of the comparative example is as follows:

[0148]

[0149]

[0150] Performance detection: The driving voltage, luminous efficiency, and lifespan of the organic electroluminescent devices obtained from Comparative Examples 1-7, Parallel Examples 1-6, and Device Examples 1-17 were characterized at a brightness of 5000 (nits). The test results are shown in Table 2 below.

[0151] Table 2

[0152]

[0153]

[0154] As can be seen from Table 2, the driving voltages of the organic electroluminescent devices provided by Device Examples 1-17 and Parallel Examples 1-6 of the present invention are 3.01V - 3.79V, which are significantly lower than those of Comparative Examples 1-7. At the same time, the luminous efficiency is higher than that of Comparative Examples 1-7, and the lifespan is significantly improved compared to Comparative Examples 1-7. This is because when a device is made with a dual-host structure, the structure is more stable, the energy conversion loss from singlet state to triplet state is smaller, so the voltage is lower, and the efficiency and lifespan are higher.

[0155] It should be noted that the present invention provides an organic electroluminescent device with a dual-host structure. By using this dual-host material, triplet excitons can be dispersed on two hosts, which can reduce triplet-triplet annihilation (TTA). While reducing the driving voltage of the organic electroluminescent device, it can also improve the efficiency and lifespan of the device.

[0156] From this, it can be known that compared with the organic electroluminescent devices prepared by using comparative compounds E-1, E-2, E-3, F-1, F-2, and F-3 as the dual-host materials of the light-emitting layer, the organic electroluminescent devices prepared by using the organic electroluminescent compounds provided by the present invention as the light-emitting layer materials have a significantly lower driving voltage, and the luminous efficiency and lifespan are significantly improved.

[0157] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A main body material, characterized in that, The structure of the host material is shown in General Formula 1-1 and General Formula 1-2: Wherein, Ring A is selected from substituted or unsubstituted (C6-C18) aryl; Ring B is selected from substituted or unsubstituted (C6-C18) aryl, substituted or unsubstituted (C6-C18) heteroaryl; Ring C is selected from hydrogen, substituted or unsubstituted (C6-C18) aryl, substituted or unsubstituted (C6-C18) heteroaryl; X is independently selected from N, O, S; L is selected from a linking bond, substituted or unsubstituted (C6-C30) aryl.

2. The main material according to claim 1, characterized in that, Ring A and Ring B are each independently selected from substituted or unsubstituted phenyl; X is independently selected from O.

3. The main material according to claim 1 or 2, characterized in that, The heteroaryl described includes monocyclic aromatic groups and polycyclic aromatic ring systems containing at least one heteroatom, and the heteroatoms include but are not limited to O, S, N; The substituted groups in the "substituted or unsubstituted" are selected from deuterium, fluorine, C1-C10 alkyl, deuterium-substituted C1-C10 alkyl, C3-C10 cycloalkyl, C3-C10 heterocycloalkyl, and the heteroatoms thereof are selected from O, S, N; or the substituted groups in the "substituted or unsubstituted" are selected from the following structures:

4. The main material according to claim 1, characterized in that, The structures of General Formula 1-1 and General Formula 1-2 include but are not limited to any one of the following compounds:

5. An organic electroluminescent material containing a dual host, characterized in that, The organic electroluminescent material containing a double host includes a first host material and a second host material. The first host material is the host material described in Claim 1, and the second host material has the structure shown in General Formula 2: Wherein, D1, D2, and D3 are each independently selected from substituted or unsubstituted (C6-C42) aryl, substituted or unsubstituted (C3-C30) heteroaryl; L1 and L2 are selected from a linking bond, substituted or unsubstituted (C6-C30) aryl.

6. The organic electroluminescent material containing a dual host according to claim 5, characterized in that, D1 and D2 are selected from (C6-C18) substituted or unsubstituted aryl; D3 is selected from substituted or unsubstituted (C6-C36) aryl, substituted or unsubstituted (C3-C30) heteroaryl; L1 and L2 are selected from a linking bond, (C6-C18) substituted or unsubstituted aryl.

7. The organic electroluminescent material containing a dual host according to claim 6, characterized in that, D1 is selected from substituted or unsubstituted phenyl, biphenyl, terphenyl; D2 is selected from substituted or unsubstituted phenyl, naphthyl, biphenyl, terphenyl, benzophenanthryl; D3 is selected from substituted or unsubstituted (C6-C30) aryl, substituted or unsubstituted (C3-C30) heteroaryl; L1 is a linking bond, and L2 is a linking bond or phenyl, naphthyl.

8. The organic electroluminescent material containing a dual host according to claim 5 or 7, characterized in that, The heteroaryl described includes monocyclic aromatic groups and polycyclic aromatic ring systems containing at least one heteroatom, and the heteroatoms include but are not limited to O, S, N; The substituted groups in the "substituted or unsubstituted" are selected from deuterium, fluorine, C1-C10 alkyl, deuterium-substituted C1-C10 alkyl, C3-C10 cycloalkyl, C3-C10 heterocycloalkyl, and the heteroatoms thereof are selected from O, S, N; or the substituted groups in the "substituted or unsubstituted" are selected from the following structures:

9. The organic electroluminescent material containing a dual host according to claim 5, characterized in that, The structure of General Formula 2 includes but is not limited to any one of the following compounds:

10. Use of an organic electroluminescent material containing a double host as described in Claim 5 in the preparation of an organic electroluminescent device.

Images